Gripper device for a heel-lasting machine

ABSTRACT

A gripper device in a heel-lasting machine, for tightly stretching a leather shank on a last, having a pair of box members disposed on opposite sides of a bracket member for supporting the last. Each box member has a set of upper and lower jaw members for gripping the shank. At least one arcuate groove is provided in each of the box members for directing movement of each respective set of jaw members along a curved path directed upwardly and outwardly away from the last defined by its gripping points. A mechanism is associated with each set of jaw members for moving each set along its respective path to stretch the shank gripped between the sets. Another mechanism moves the gripper device longitudinally along the last for stretching the shank to closely follow a surface of a heel part of the last for moulding thereon.

United States Patent 1 Schindler et al.

GRIPPER DEVICE FOR A HEEL-LASTING MACHINE Inventors: Herbert Schindler, Pirmasens;

Gerhard Winter, Hauenstein, both of Germany Firma Schoen & Cie Gesellschaft mit Beschrankter l-laftung, Pirmasens, Germany Filed: July 12, 1972 Appl. No.: 271,023

Assignee:

[45 Feb. 26, 1974 Eastman l2/14.5

Weinschenk 12/14.5

57 ABSTRACT A gripper device in a heel-lasting machine, for tightly stretching a leather shank on a last, having a pair of box members disposed on opposite sides of a bracket member for supporting the last. Each box member has a set of upper and lower jaw members for gripping the shank. At least one arcuate groove is provided in each of the box members for directingmovement of each respective set of jaw members along a curved path directed upwardly and outwardly away from the last defined by its gripping points. A mechanism is associated with each set of jaw members for moving each set along its respective path to stretch the shank gripped between the sets. Another mechanism moves the gripper device longitudinally along the last for stretching the shank to closely follow a surface of a heel part of the last for moulding thereon.

9 Claims, 3 Drawing Figures 1 GRIPPER DEVICE FOR A HEEL-LASTING MACHINE BACKGROUND OF THE INVENTION This invention relates to a gripper device for a heellasting machine for tightly stretching the shank on the last by means of tong-like grippers approximately within an area extending on both sides of the last point support. It relates particularly to a gripper device for a heel-lasting machine of a type in which the last is so disposed in the machine that the sole mounted thereon faces upwards.

The working procedure of machines of this type is such that the shank edge is tucked in and onto an adhesive-coated insole by so-called shears or wipers or tuck-in devices, and cemented thereto. In machines of this type the shank is gripped by tong-like grippers mostly at the last point and stretched in forward direction, i.e., away from the last tip. The forepart of the shank is frequently pulled upwards at the same time by a separate gripper arrangement, so that the shank leather is tightly stretched both over the heel and over the forepart of the last. These stretching and lasting procedures frequently lead to the formation of creases, particularly in the instep area of the last.

It has now been surprisingly found that such difficulties are eliminated when the gripper arrangement carries out a movement based upon the present invention. Creases are entirely eliminated particularly when the gripper arrangement, when tightening the shank leather and additionally to its upward movement away from the last body, possess an additional movement component in a direction towards the last axis.

SUMMARY OF THE INVENTION It is accordingly an objective of this invention to provide an improved stretching procedure prior to the lasting and cementing steps. Above all, creasing of the shank leather should be entirely eliminated, particularly within the instep area of the last.

The gripper arrangement based upon the invention and of the type described hereinbefore is characterized in that the gripper members are so guided during their working cycle that the path described by their gripping points at least during its last segment possesses a component directed inwardly towards a plane extending through a longitudinal axis of the last, i.e., a plane assumed to be extending through a longitudinal and central axis of the last and at right angles to the sole of the last.

The gripping points preferably describe an upwarddirected path away from the sole on the sole side of the last and aligned towards a plane extending through a longitudinal axis thereof. The aforementioned gripping points of the gripper arrangement advantageously describe a curved path and one whose curvature is concave as seen from the direction of the sole. This path can be so shaped that, when looking from the front towards the tip of the last with a sole horizontally mounted thereon, the curvature centerpoints form a perpendicularly extending prism whose cross-section is determined by the sole.

The surface lines of the above prism thus coincide with the line of vision towards the sole in its greatest surface area. The path described by the gripping points BRIEF DESCRIPTION OF THE DRAWINGS I Having in mind the above and other objects that will be evident from an understanding of this disclosure, the

V invention comprises the devices, combinations and arrangements of parts as illustrated in the presently pre ferred embodiment of the invention which is hereinafter set forth in such detail as to enable those skilled in the art readily to understand the function, operation, construction, and advantages of it, when read in conjunction with the accompanying drawings in which:

FIG. 1 illustrates a simplified side elevational view of a part of a heel-lasting machine with upward-facing last bottom and ancillary tuck-in means, and a'gripper arrangement pursuant to the present invention, with certain elements of the machine being shown in section;

FIG. 2 illustrates a front elevational view in section through the gripper arrangement of FIG. 1, the gripper arrangement being shown open and in a rest position; and

FIG. 3 illustrates a front elevational view insection through the other half of the gripper arrangement of FIG. 1, corresponding to FIG. 2,- and showing the gripper arrangement after it has stretched the shank leather, where for the sake of simplicity, the composite figure thus represents two different working positions, with FIGS. 2 and3 each showing one-half of a sectional view.

DETAILED DESCRIPTION OF THE INVENTION Referring now to FIG. 1 of the drawings, brackets 2 and 2', which serve as support and guide means for tuck-in tools 3, are anchored in a frame 1. Tuck-in tools 3 are journalled in base-plates 4. The tools are conventionally driven by hydraulic or pneumatic means via suitable linkage systems (not shown). A last 7 is braced from above by a conventionally mounted member 5. A cement applicator device 6 is also conventionally mounted above the last 7. A shoe shank 8, to be bonded to the insole, surrounds the last 7 which carries an insole 9. The last 7 is mounted on a pin 10 which threads a bore 7 in the last body, with pin 10 itself being accommodated in an adjustable block 11. Block 11 is supported by a bracket 13, its height being conventionally adjustable therein by means of a milled knob 12 and associated thread.

The lower end of bracket 13 extends into a piston 14. Above piston 14, the substantially pillar-like bracket 13 accommodates a cylinder 15 provided with a bore 15' which extends substantially horizontally, i.e., transversely to the longitudinal axis of bracket 13, and accommodates a piston 16 with a connecting rod 17 which extends from cylinder 15. A detailed explanation of the operation of this arrangement becomes superfluous after a careful examination of the drawing, which is self-explanatory.

The front end of connecting rod 17 carries a bearing block 18. A substantially horizontally disposed pin 21 anchors a shackle 19 of a sliding carrier 20 to the bearing block 18, so that shackle 19, hearing block 18 and pin 21 together form a pin joint with a horizontal axis. The piston/cylinder arrangement 16, 15 is actuated hydraulically or pneumatically using a pressure medium introduced through inlet 43.

Carrier 20 is slidingly displaceable in reciprocate fashion along horizontally-disposed guideway 39 (see drawing). A bracket 22 which carries a transverse bearing 24 extends upwards from sliding carrier 20. The elevation of the transverse bearing 24 over carrier 20 is conventionally adjustable by means of a milled knob 23 and associated thread 24'. A bracket 26, the elevation adjustment of which is conventionally controlled by a milled knob 25 and associated thread, supports the tip of the last 7, when the latter is mounted in the machine.

Transverse bearing 24 carries bearing boxes 27 with guide grooves 27' on both sides of the last. Bearing boxes 27, as best shown in FIGS. 2 and 3, are provided with cylindrical bores 28 which accommodate pistons 29 displaceable therein under hydraulic pressure. The pressure medium is introduced into the cylinder bores 28 through pressure lines 30. The crown of each piston 29 actuates a lobe 31 of the gripper arrangement via a shackle 44. The lobe 31 can be urged upwards by piston 29 and returned into its initial position by a convention spring (not shown).

During these above-mentioned movements, lobe 31 is guided in the arcuate groove 27'. The curvature center-point associated with the configuration of groove 27', i.e., in this case the pivot point for the gripper arrangement and the gripping point thereon, coincides with point 34, shown in FIGS. 2 and 3, i.e., in vertical projection within the last edge and somewhat above the insole. The upper jaw member 35 is actuated by a piston 36 supplied with the pressure medium via a pressure line 37. Piston 36 and the upper jaw member 35 are biased back into their initial positions by a spring 38.

A hydraulic cylinder 40 associated with the piston 14 is accommodated at a point-of-support 41 in the machine frame 1. The piston/cylinder arrangement 14, 40 is supplied with pressure medium through a pressure line 42. The hydraulic system can be readily replaced by a gear system which would operate the gripper arrangement by means of suitable mechanical linkage. The gripper movement based upon the principle of the invention can be likewise carried out in two separate movements, with each movement being effected by a separate drive system.

The novel device is operated as follows: The last 7, with the insole 9 and shank 8 disposed thereon, is mounted with its bore 7' on last pin 10. Cylinder 40, with its piston 14 and bracket 13, is pivoted around pivot point 41 so as to adopt the position I indicated by a dot-dash line in FIG. 1. The support bracket 26 is then moved into abutment against the last tip. The entire arrangement 40, 14, 13 with all the elements attached thereto is then pivoted around pivot point 41 until the longitudinal axes of members l0, 13, 40 and 41 adopt a substantially perpendicular position as shown in FIG. Land is locked in this position. The resulting position II of sliding carrier 20 and bracket 22 with the gripper arrangement is likewise indicated by a dot-dash line in FIG. 1.

In this above-mentioned position, the edge of the shank 8 is located between the lower jaw 31 and the upper jaw 35 of the gripper arrangement (FIG. 2). A switch (not shown), e. g., a foot-operated switch, is now actuated to initiate the operation of piston 36 to close the gripper arrangement and thus grip shank 8.

Cylinder 15 is then filled withthe pressure medium, which actuates its piston 16 thereby moving carrier 20 with bracket 22 along guideway 39. This results in the gripper arrangement being also entrained, thus so stretching the shank 8 that it closely follows the surface of the heel part of last 7 and is moulded thereon.

The end-portion of piston 16 in cylinder.l5 is determined either by a pull on the shank leather, or by means of limit switches (not shown) arranged along guideway 39 to co-operate with cams (not shown) arranged on the carrier 20. The switch array acts on a system of electrical and hydraulic networks (not shown) which controls the pressure medium for the cylinder.

Piston 29 in cylinder bore 28 is actuated by the pressure medium in a largely automatically-controlled program, as a result of which the entire lower gripper jaw 31, guided by the arcuate groove 33, slides along guide groove 27. The gripper arrangement thus moves along an arcuate path around an imaginary point 34. FIG. 3 shows the end-position of the gripper arrangement.

Accordingly, the gripper jaws 31, 35 are so guided during their working cycle that the path described by their gripping points, at least during its last segment, possesses a component directed inwardly towards a plane extending through a longitudinal axis of the last 7. The gripping points describe an upward-directed path away from the sole on insole 9 on the sole side of the last 7 and aligned towards a plane extending through a longitudinal axis thereof. The aforementioned gripping points of the gripper arrangement advantageously describe a curved path and one whose curvature is concave as seen from the direction of the sole. This path can be so shaped that, when looking from the front towards the tip of the last with a sole horizontally mounted thereon, the curvature centerpoints form a perpendicular extending prism whose cross-section is determined by the sole. The surface lines of the prism thus coincide with the line of vision towards the sole in its greatest surface area. The path described by the gripping points can adopt the configuration of an arc. The center-point of such an arcuate path is advantageously located within the outline of the last, approximately at the height of the insole, thereabove, or therebelow.

In the above-mentioned end-position, the edge of shank 8 is particularly well placed for the tuck-in procedure. Tripped by the control means (not shown) the tuck-in tool 3 moves inwards and forces the shank edge against the insole 9, whereupon the cylinder/piston arrangement 40, 14 is actuated and urges the tucked-in shank edge against the tuck-in tool 3 to assure a faultless fit. The tuck-in procedure is known per se as executed by other machines and thus will not be described here in greater detail.

All elements of the machine are returned into their respective initial positions in response to the actuation of a foot-operated switch (not shown). The shoe, with its heel part lasted, can now be removed from the machine.

In case of any doubt, all characteristic features disclosed hereinbefore are to be considered as essential to the inventive concept as a whole both severally and in all effective combinations. Patent protection is desired for all patentable subject matter, notwithstanding any possible erroneous interpretation of the state of the art on the part of the inventor.

Numerous alterations of the structure herein disclosed will suggest themselves to those skilled in the art. However it is to be understood that the present disclosure relates to a preferred embodiment of the invention which is for purposes of illustration only and not to be construed as a limitation of the invention.

What is claimed is:

l. A gripper device for a heel-lasting machine for tightly stretching a shank leather on a last by means of a gripper arrangement approximately within an area extending on both sides of a last tip support,

characterized in that a guiding member guides said gripper arrangement during its working cycle, said gripper arrangement including a gripper jaw, said guiding member including arcuate means along which said gripper jaw slides for directing movement of said gripper jaw along a curved path defined by gripping points of said gripper arrangement, said curved path possessing a component directed toward a plane extending through a longitudinal axis of said last at least during a last segment of said curved path.

2. A gripper device as claimed in claim 1, characterized in that said gripping points adopt an upwarddirected path away from a sole on a sole side of said last and aligned toward said plane extending through said longitudinal axis.

3. A gripper device as claimed in claim 2, characterized by said curved path of said gripping points, having a curvature which is concave as seen from a direction of said sole.

4. A gripper device for a heel-lasting machine for tightly stretching a shank leather on a last by means of a gripper arrangement approximately within an area extending on both sides of a last tip support,

characterized in that guiding means guide said gripper arrangement during its working cycle to describe a path defined by gripping points of said gripper arrangement, said path possessing a component directed toward a plane extending through a longitudinal axis of said last at least during a last segment of said path, said path described by the gripping points including an arcuate configuration, an arcuate groove and a member guided therein serving as said guiding means for said gripper arrangement.

5. A gripper device as claimed in claim 4, characterized in that a center-point of an arc of said arcuate path within an outline of said last is located at an approximate height of an insole mounted on said last.

6. A gripper device for a heel-lasting machine, for tightly stretching a leather shank on a last, said gripper device comprising a pair of box members disposed on opposite sides of a bracket member for supporting the last, each box member being provided with a set of upper and lower jaw members for gripping the shank, guide means associated with each of said box members for directing movement of each respective set of said jaw members along a path defined by gripping points, and means for moving each set of jaw members along its respective path to stretch the shank gripped between said sets.

7. A gripper device as claimed in claim 6, wherein said guide means includes at least an arcuate groove provided in each of said box members fordirecting movement along a curved path.

8. A gripper device as claimed in claim 7, including means for moving said gripper device longitudinally along the last for stretching the shank to closely follow a surface of a heel part of the last for moulding thereon.

9. A gripper device for a heel-lasting machine for tightly stretching a shank leather on a last by means of a gripper arrangement approximately within an area extending on both sides of a last tip support,

characterized in that guiding means guide said gripper arrangement during its working cycle to describe a path defined by gripping points of said gripper arrangement, said path possessing a component directed toward a plane extending through a longitudinal axis of said last at least during a last segment of said path, said path defining a curved path described by said gripping points, said curved path including curvature center-points which, when looking from a front towards a tip said last with a sole horizontally mounted thereon, define a perpendicularly extending prism within a certain space, cross-section of said prism being determined by dimensions of said sole. 

1. A gripper device for a heel-lasting machine for tightly stretching a shank leather on a last by means of a gripper arrangement approximately within an area extending on both sides of a last tip support, characterized in that a guiding member guides said gripper arrangement during its working cycle, said gripper arrangement including a gripper jaw, said guiding member including arcuate means along which said gripper jaw slides for directing movement of said gripper jaw along a curved path defined by gripping points of said gripper arrangement, said curved path possessing a component directed toward a plane extending through a longitudinal axis of said last at least during a last segment of said curved path.
 2. A gripper device aS claimed in claim 1, characterized in that said gripping points adopt an upward-directed path away from a sole on a sole side of said last and aligned toward said plane extending through said longitudinal axis.
 3. A gripper device as claimed in claim 2, characterized by said curved path of said gripping points, having a curvature which is concave as seen from a direction of said sole.
 4. A gripper device for a heel-lasting machine for tightly stretching a shank leather on a last by means of a gripper arrangement approximately within an area extending on both sides of a last tip support, characterized in that guiding means guide said gripper arrangement during its working cycle to describe a path defined by gripping points of said gripper arrangement, said path possessing a component directed toward a plane extending through a longitudinal axis of said last at least during a last segment of said path, said path described by the gripping points including an arcuate configuration, an arcuate groove and a member guided therein serving as said guiding means for said gripper arrangement.
 5. A gripper device as claimed in claim 4, characterized in that a center-point of an arc of said arcuate path within an outline of said last is located at an approximate height of an insole mounted on said last.
 6. A gripper device for a heel-lasting machine, for tightly stretching a leather shank on a last, said gripper device comprising a pair of box members disposed on opposite sides of a bracket member for supporting the last, each box member being provided with a set of upper and lower jaw members for gripping the shank, guide means associated with each of said box members for directing movement of each respective set of said jaw members along a path defined by gripping points, and means for moving each set of jaw members along its respective path to stretch the shank gripped between said sets.
 7. A gripper device as claimed in claim 6, wherein said guide means includes at least an arcuate groove provided in each of said box members for directing movement along a curved path.
 8. A gripper device as claimed in claim 7, including means for moving said gripper device longitudinally along the last for stretching the shank to closely follow a surface of a heel part of the last for moulding thereon.
 9. A gripper device for a heel-lasting machine for tightly stretching a shank leather on a last by means of a gripper arrangement approximately within an area extending on both sides of a last tip support, characterized in that guiding means guide said gripper arrangement during its working cycle to describe a path defined by gripping points of said gripper arrangement, said path possessing a component directed toward a plane extending through a longitudinal axis of said last at least during a last segment of said path, said path defining a curved path described by said gripping points, said curved path including curvature center-points which, when looking from a front towards a tip said last with a sole horizontally mounted thereon, define a perpendicularly extending prism within a certain space, cross-section of said prism being determined by dimensions of said sole. 